CODEWITHSUNDEEP
r
dMh
dMh

Reputation: 27

Determining response time in R

I have a running list of 2 variables which include a date and time component. The form of these variables are: 

2015-08-29T11:52:04
2015-08-29T11:52:19

I would like to extract the time sections from the variables above (i.e. everything after 'T') and calculate the difference to determine a response time (i.e. 15 seconds in this case)

Looking for some guidance on how to approach this with R. I found a similar solution (Extracting time from a date/time format) but am having difficulty applying the solution to my problem here.

Would appreciate any guidance! Thanks in advance.

Upvotes: 1

Views: 291

Answers (2)

akrun
akrun

Reputation: 887221

We can convert to ITime and calculate the difference. Based on the OP's post, we need to remove the prefix 'Date' up to 'T' and then use only the time part for calculating the difference

library(data.table)
diff(as.ITime(sub('.*T', '', str1)))
#[1] "00:00:15"

Or another option is to convert the full string to DateTime with ymd_hms, convert to ITime and get the difference

diff(as.ITime(ymd_hms(str1)))
#[1] "00:00:15"

Or with lubridate

library(lubridate)
as.numeric(diff(ymd_hms(str1)))
#[1] 15

Or with difftime in base R after converting to Datetime class with as.POSIXct

dtime <- as.POSIXct(str1, format = "%Y-%m-%dT%T")
as.numeric(difftime(dtime[2], dtime[1], unit = 'sec'))
#[1] 15

Or as @Onyambu suggested

diff(strptime(str1,"%FT%T"))

data

str1 <- c("2015-08-29T11:52:04", "2015-08-29T11:52:19")

Upvotes: 1

Ronak Shah
Ronak Shah

Reputation: 389045

In base R, we can convert the time to POSIXct class and use difftime to calculate difference between the two specifying units as required. 

time1 <- '2015-08-29T11:52:04'
time2 <- '2015-08-29T11:52:19'

as.numeric(difftime(as.POSIXct(time2, format = '%FT%T'), 
                    as.POSIXct(time1, format = '%FT%T'), units = 'secs'))
#[1] 15

Upvotes: 2

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